Find out if your YAML parses, and where it does not.
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How to use YAML Validator
Paste your YAML.
Read the message. Green means valid, red shows the problem.
Open the Tree view to see how the values were parsed.
About YAML Validator
YAML errors are rarely about missing brackets. They are about one space too many or too few, a tab where spaces should be, or a colon in a value that was not quoted. The validator runs a full parse and shows you the line and column where the parser gave up.
On success you get a normalised version of your file, and the tree view shows how it was understood. That is a good way to check that a list is really a list and a number is really a number.
Frequently asked questions
Why does my YAML fail with a tab error?
YAML does not allow tabs for indentation. Replace them with spaces, most editors can do that automatically.
What does "bad indentation of a mapping entry" mean?
A key is indented differently from its siblings, or a list item sits at the wrong depth. Look at the line mentioned and compare it with the lines above it.
Does this check Kubernetes or Docker Compose rules?
No, only YAML syntax. It will tell you the file parses, not that the keys are valid for your tool.
Are multi-document files supported?
Yes. Documents separated by --- are read, and shown as a list in the tree.
Why is a value shown as a string in quotes?
It looks like a number or boolean that must stay text, such as "yes" or "0123". The validator quotes those in the normalised output.